Biologists have developed a technique for establishing colonies of human embryonic stem cells without killing embryos, a method that, if confirmed in other laboratories, would seem to remove the principal objection to stem cell research.
?There is no rational reason left to oppose this research,? said Dr. Robert Lanza, vice president of Advanced Cell Technology and leader of a team that reported the new method in an article in today?s Nature. But critics of human embryonic stem cell research raised other objections, such as the possible risk to the embryo and the in vitro fertilization procedure itself in which embryos are generated from a couple?s egg and sperm.
The new technique would be performed on an embryo when it is two days old, after the fertilized egg has divided into eight cells, known as blastomeres. In fertility clinics, where the embryo is available outside the mother in the normal course of in vitro fertilization, one of these blastomeres can be removed for diagnostic tests, such as for Down?s syndrome, and the embryo, now with seven cells, can be implanted in the mother if no defect is found. Many such embryos have grown into apparently healthy babies over the ten years or so the diagnostic tests have been used.
Up to now, human embryonic stem cells have been derived at a later stage of development when the embryo consists of about 150 cells. Harvesting these cells kills the embryo.
Last year, Dr. Lanza reported that embryonic stem cell cultures could be derived from the blastomeres of mice, a finding others have confirmed. He now says the same can be done with human blastomeres. Although he used discarded human embryos in his experiments, he said that anyone who wished to derive human embryonic stem cells without destroying an embryo could use a blastomere removed for the test, called pre-implantation genetic diagnosis. ?By growing the biopsied cell overnight, the resulting cells could be used for both PGD and the generation of stem cells without affecting the subsequent chances of having a child,? he said.
Ronald M. Green, an ethicist at Dartmouth College and an adviser to Advanced Cell Technology, said he hoped the new method ?provides a way of ending the impasse about federal funding for this research.?
He said he believed the method should be seen as compatible with the Dickey-Wicker amendment, the Congressional action that blocked the use of federal funds for research in which a human embryo is destroyed or exposed to undue risk.
Facebook
Twitter